Electrical control apparatus



May 13, 1941. A. w. PLENsLER. ETAL 2,241,715

ELECTRICAL CONTROL'APPARATUS' v FiledAug. 30, 1938 '7 Sheets-Sheet 1 4272 +5 #JV/f 43%,. ffii@ May 13, 1941. w. PLENSLER Erm. '22415715 ELECTRICAL CONTROL APPAATUS I Filed Aug. 3o, 1938*/ 7 sheds-sheet 2 fjfg 'l O 5g O HI if. 45X y A )u II Z3 /f/ r i fzlllll j] O Il L] l i 5f, HI ll J;

.7 ,.42 y] '1f l?) ill /'i 3f f ml; l mw. m, lbf {I} f Q JQJ www2/1M May 13, 1941- A. w. PLENSLER ETAL 2,241,715

ELECTRICAL CONTROL APPARATUS l Fned Aug. so, 195s 7 sheets-sheet s ffv May 13, 1941.

A. W. FLENSLER ELECTRICAL CONTROL APPARATUS Filed Aug. 3o, 1958 7 sheets-sheet L May 13, 1941.

A. W. PLENSLER ET AL ELECTRICAL CONTROL APPARATUS '7 sheets-sheet 5 Filed Aug. 50, 1938 May 13,1941. A. w. PLENsLER ET AL ELECTRICAL CONTROL APPARATQS 7 Sheets-sheet s Filed'Aug. 30, 1938 v @WQ/j.

May-13, 1941- A. w. PLENsLER E-rAL 2,241,715

A ELECTRICAL CONTROL APPARATUS -Filed Aug. 5o, 1938 7 sheets-sheet? ez/ J:

fw 105m aff'.

I 6--6 of Fig. 1 showing Pacman@ 13, 1941 UNITED STATE ELEo'rmoAL CONTROL Arraaarns Alexander' W.

Plensler and Richard C. Marhol'z,

Chicago, Ill.,` assignors to Belmont Radio Corporation, Chicago, Ill.,l a corporation of Illinois Appn'caticn'augnst 3o, 1938,"ser1a1 N0. 221,525

15 claims. (c1. 192-14'2) l section of the torsion-springconnection:between Our invention'relates in general to so-called automatic tuning for radio receivers, and more particularly to an electrically operated tuning apparatus for a radio receiver. which can be successfully operated from a remote or an adjacent position. A

According to the present invention, thercam and lever structure of the mechanically operated tuning apparatus'of copending Plensler application, Serial No. 170,070, is utilized in an electrically o'perated `tuning apparatus which maybe controlled yfrom a remote .or an adjacent position, as contrasted to the mechanical tuning apparatus of the above'identifled application which is operated directly at the lapparatus ,and entirely by manual means. f

' `The embodiment ofthe present invention is provided in a sturdy, simplified, and inexpensive apparatus whichY is operated Y by an electrical circuit which itself is extremely simple, and requires a very minimum number of contacts so that the assembly and original adjustment of the device is accomplished in a very expeditious and eilicient manner, and subsequent servicingl v of the unit is substantially eliminated.

Other features and advantages of the invention will be apparent from the following' description and the drawings, in which:

Fig, 1 is a front elevation of the tuning control apparatus according to one embodiment of our invention;

Fig. 2 is a cross-sectional view taken along the line 2-2 of Fig. 1;l f

Fig. 3 is a view of the structure illustratedin' Fig.- 2, with the control' elements in the final predetermined control position, and hence in an advanced position' with respect to the starting position of such elements in Fig. 2;

Fig. '4 is a cross-sectional View line 4-4 of Fig. 1 and showing the control elements at this point in starting position;

Fig. 5` is a view of the structure of Fig. 4 showiing such structure in the final adjusted control position; Fig. 6 is a cross-sectional view along the line the driving and control elements in a position assumed when two control buttons are' pressed at the same time substantially;

Fig. 'l is an end elevation looking at the lefthand'end of the structure illustrated in Fig. V1 and in the direction of the karrows along the line 1-1 of such figure;

Fig. 8 is a 'perspective view in detail of the pivotal latching member from the structure of Fig. 1; I l

Fig. 9 is a perspective view Of the stop member for the selector levers of the structure of Fig. 1:

Fig. 10 is a fragmentary detail principally in taken`along the the driving arms and latch members illustrated in both of the embodiments of .our invention shown and described in this application;

Fig. 11 is a sectional view looking in the. direction of the arrows along the line II--II lof Fig. 1; Fig. 12 is a horizontal view partly in'section along the line I2'--I2 of'Fig. 1;'

Fig. 13 is a front elevation of another embodiment-,of our invention;

Fig. 14 is a fragmentary cross-sectional view along the line` I4-I 4 of Fig. 12; and

Fig. 15 is a schematic illustration of the circuit and associated elements for both embodiments of the invention.

.Referring now to the drawings -,Fig. 1 `illustrates tuning apparatus mounted on a chassis I0 for a radio receiver andincluding'a'preassembled tuning unit I I connected with a tuning condenser I2 for angular adjustment of the latter. 'I'he mechanism itself is supported on a frame including end plates I3 and I4, with the latter secured to end plate I8 of the condenser frame which inturn is supported from the chassis.` A

shaft I1 (Fig. 2), is connected to, or is integral with, the shaft for the tuning condenser I2. 'I'he shaft Il is appropriately Journalled inthe' tuner frame and supportsrthereon a plurality of heartshaped control members I8 angularlyadjustable with vrespectl to'the shaft I1, and frictionally retained by means of friction washers I9 non-g rotatable but axially movable with reference to the shaft. and axially slidable sleeves 2| inter mediate each pair of friction Washers. The frictional pressure intermediate the'washers I9 and `control members I8 is varied in accordance with the axialy position of an internally threaded friction gear 22 as will be hereinafter more specifically descriced. The control `members I8 are se member I8 is moved by theengagement of the4 roller 24 on the lever against theedge oi.' the control member, and the transmission of the movement of the lever therethrough. The control member is rotated until the roller 24 is seated in the depression 28 in the control member as shown in Figs. 3 and 5, for instance. This general structure and operation is more fully disclosed in the copending Plensle'r application identied above.`

Preselective pivotalmovement is imparted lto the selector levers 23and 23.' by means of `a unidirectional electrio motor M connected by an appropriate train of gears 28 with a driven member' 29 which 'acts to control theoperation of the main switch for the tuner circuit, and also to indirectly drive the selector levers. Themember 2 9 is not connected into an ele'ctric circuit in any way, but for-convenience in differentiating it from the other elements it will be referred to as a commutator disc. The commutator disc 29 is supported for complete rotary movement on a stub shaft 39 carried on the tuner frame, and such disc 29 is connected through a roller 3| thereon with a driving arm 32 pivotally supported on the shaft 24, as may be seen more clearly in Fig. 10. The driving arm 32 in turn is connected with'a latch member 33 likewise pivotally supportedl on the shaft 24. In order to permit relative movement as between the driving arm 32 and latch member 33, during a portion of 'a complete operating cycle, as will be hereinafter described, such arm and member are connected only by arelatively stiff torsion-spring 39 hooked into the driving arm and latch member as'can be seen in Fig. 10, and supported on the bushing 31carry1n8 the driving arm 32. The entire driving force of the arm 32 is transmitted through such spring, hence it is understood that the spring must be stiff enough to accommodate this force and maintain the two members substantially together through the operating stroke. A stop 35 on the arm 32 prevents the latch member from dropping away from the driving arm in va clockwise direction, as viewed in Figs'. 2, 3, 4,

5, 6, 'and 14, but `does not prevent the driving arm from moving ahead of the latch member in a` particularly in Figs.`

clockwise directionas noted andfhand 'as will bemore fully'described. Normal-ly, the force of the spring under tension secured at its opposite ends' as described, maintains the leg of the latch member 33 against the face oi' the stop 35.

The latch member 33 is illustrated in detail in Fig. '3, and comprises a substantially U-shaped member having a. pair of supporting legs 38 and a crl'asspiece- 39 including alternate projecting portions 4 i', and cavities 42. In order to conserve as much space as possible axially oi the tuner unit, alternate selector levers are staggered in their upper portions so as to provide for a similar staggered relation for the locking electromagnets as shown in Fig. 4. One group of selector levers, as illustrated in Figs. 2 and 3, and designated by the reference character 23, in-

cludes an upper portion 43 disposed at a `relatively small angle with reference .to .the lower portion 44jof the lever. The selector levers 23 such as shown in Figs. 4 and 5 have the lower portions 44 separated by a greater angle from the upper portionsy 45 than is the case with the eorrespond` ing portions of the levers 23. The' lower portion 4 of each type of selector lever is substantially identical. The latch member 33 with va preselected selector lever to drive the latter4 by means of a slidable plunger 41 carried in integral ears 48 stamped out of each lever. The plunger has an enlarged head which hooks over the edge of the latch member when the former is drawn upwardly to temporarily lock the latch member and lever together as shown in Figs. 3, 5, and 6. A spring 49 Vcarried on each plunger, rests intermediate the top ear 49 and a washer 5i secured to the plunger to be compressed when the plunger is drawn upwardly and. then act to retract the plunger when the tuning operation is completed.

Each plunger 41 may be selectively drawn upwardly in a lever upon energization of a correispending electromagnet 52. The electromagis connected v is attracted to the v nets are insulatingly supported from brackets 53 secured in the tuner frame, and correspond in number to the selector levers 23y and 23'. Each electromagnet 52 is electrically connected into a circuit including a push button or the like 54 (Fig. 15) which may -be carried on a remote con.. trol unit, or mounted on the front of the radio receiver cabinet. Each electromagnet and its corresponding push button are connected in series, and each such set is connected in parallel with the other sets asis clear from Fig. 15. 'I'he complete operating circuit extends from a source of currentaC, through the various sets of electromagnets and push buttons through a multileal' switch S, and a motor M, back to source C. Upon operation oi' a selected push button 54 the circuit is closed from Ithe source C, and the corresponding electromagnet 52 is energized to attract the plunger 41 of the corresponding selector lever 23 or 23' to the face of the core in the magnet. The'circuits extends from a push but-l ton through conductor 59 and switch contacts 51, which are normally in closed' position, to the motor M which is illustrated diagrammatically in Fig. 15 centrally of the enlarged commutator discl 29. Simultaneously with the energizatlon of the motor M, the commutator -disc 29 vis rotated thereby. The commutator disc is provided with a cavity or recess 53 in which a switch arm 59 rests when the unit is in idle position with the contacts 51 of the switch S closed.

However, as the commutator disc 29 is roltated, the switch arm 59 moves out of the recess 58 following the contour of the edge of the commutator disc to open the switch at the contacts 51, and close the switch at' the contacts 5i. 'I'he switcharm v59 is insulatinglysecured to an inter mediate movable switch member 92 carrying a contact 51 on one side and a. contact 6I on the other side to engage one or the other of the contacts with its corresponding element depending upon the position ol' the anni 59 riding on the edge of the disc 29. The operator must push on a button only long enough to permit the disc 29 to rotate to a. point where `the contacts 51 are opened. vWith. the opening; of the contacts 51 and the closing of contacts 6I', the electromagnet is cut out of the operating circuit and a resistance 54 cut in corresponding substantially in value to the resistance of the electromagnest so .that the motor remains energized and the voltage in the motor circuit remains substantially the same until the commutator disc 29 has passed substantially through 360. At this time the switch arm 59 re-enters the recess 59 in the commutator disc, the circuit is broken at the contacts 8|, and the motor is deenergized. The movand interconnecting' armsat the end thereof as shown at'21 in Fig. 1.

In the mechanical movement corresponding to the electrical operation described above, the driving arm 32, in engagement with the roller 3| on the disc 29, is pivoted to pivot the latch member 33 in a clockwise direction as viewed in Figs. 2 to 5, inclusive. In the meantimea plunger 41 energized selected electromagnet, and the forward edge of one of the portions of the moving latch member 33 engages the shank of the plunger and its associated selector lever therewith. The shank of each of the plungers 41 is long enough so that it is retained in both of the ears 43 -on the selector lever to l number may originally guide the plunger, and subsequently transmit the moving'force'from the latchmember through the plunger to the selected selector 'to a predetermined broadcast station setting .represented'by'ithe button 54 originally pushed when the roller 24 is completely Vseated in therecess- 26 in the heart-shapedcontrol:member il. This is shown in Figs. 3 and, 5. v

m the illustrated e bodlments of the invenedge oi the latch member 33 a distance'corresponding to the radial distance the driving arm must be moved to permit the roller 3l tol clear such arm, as shown in Figs. '3 and 5. In the posi tion of `the mechanism' in each o' these figures, the engaged edge of the driving arm 32 is at right angles to a radial line through the centers of the commutator disc and roller thereon. After the roller 3| haspassed the peak position, as just described, the force of the various springs including the torsion 'spring 36, the .retracting spring 61 on the latch member 33, and the re- Y tracted spring 66 on'the selected selector lever,

tion, six control-member-selector-lever units are shown. It is understood, of course, that this be varied. `In the embodiment of Figs.l l to 9, the selected plungers for the selector levers 23-are engaged by the leading edges of the correspondingportion 4| of the latch member 33, -while the selected plungers for the selector levers 23', staggered with respect to the first group are engaged by the leading edges of the corresponding portions 42 of the latchmember.

As described above, the latch'rliembetV 33 is driven, entirely by virtue Aofthe connection with pulls the operating mechanism in a v,counter- -clockwise direction, with the driving arm 32101- lowing the roller 3i, until the mechanism is in `idle position as shown in Figs. 2 and 4. A stop member 69 having alternate projections 1I and recessed portions 12, with rubber bumpers on the leading edge of each, is mounted on the tuner frame in a position to stop the latch member and selector levers in a predetermined retracted .position.. The staggered configuration of the member 69 corresponds with that of the latch member 33 as previously described. In the idle or retracted positid',`the engaged leading edge of the latch member is spaced from the stop position of the `selected selector lever so that the'plunger 41 the driving arm 32 throulhthe torsion spring 26.

Except for this connection, the latch member is entirely free to pivot on the shaft 24 "as is ap parent from the illustration o f Fig. 10. .The tension vin the4 spring 36 is .sujicient' when l'applied through the two end portions of .the spring to maintain the latch member 33against the stopv 35 on the driving arm, andsuch tension is also sufficient to maintain the members in this posi-Y tion-duringV the movement of the latch member to drive a corresponding' control unit including a control member and selector lever. Inasmuch as the selector lever normally lis pivoted considerably less than 180, f (in onecommercial embodiment of this structure, approximately 40) depending, ot course, upon-the period of rotation of the shaft l1 having the: condenser thereon, and the Shape ,of the intermediate control member I3,

thereon is dropped to idle position under the pressure of its spring 49.

As can be understood t Figs. 2, 4, and 15, the contacts 51 on the switch S are engaged only. momentarily, that is, only so long as it requires the switch arm 59 to move out of the recess 58 in the commutator disc. As soon as the circuit through the contacts 51 is broken, the parallel push-button-electromagnet circuits are opened and cannot be closed until the circuit is again ,established through' theV contacts 51. This makes it impossible to energize a second electromagnet to attract a correspondingr plungerv 51, While a previously energized operating circuit is in operation, and as a result, there can be no means must be provided to disengage the com mutator disc which rotates through 360.from the driving arm ,moving iny accordance with av selector lever. Furthermore, it is-jnecessary to insure that the selector lever 23 or 23'-y be pivoted and the control member I.8 be movedv therewith a distance .such that the roller 24 accurately seats in the recess 26 of the control member. These prob-v lems are solved with the torsion spring and `cooperating connection between the .driving arm and latch member. The commutator disc 29 is positioned with referenceto a selector lever so that .the roller 24 is seated in the recess 26 at a time, in the complete cycle of operation, before the driving armv 32 stands precisely at an angle of 90 with a radial line through the center of the lstub shaft 30,. and the center of the roller 3| on the commutator disc. Inasmuch as the selector lever and consequently the latch member 33 locked 'therewith are stopped at the seated positio'n for the roller 24, the driving arm would normally act to stop the rotation of the commutator disc 29. However, the torsion spring 36 will yield suiiciently upon the continued rotation of the commutatorv disc 29 to permit theroller 3i Vto slide along the engaged edge of the driving arm` event that two or more push-buttons 54 are man.

ually operated simultaneously to energize.' the corresponding electromagnets 52 and hence attract the corresponding plungers v41, the rselector levers carrying such plungers will be connected with the single latch member 33. Howevenwith two or. more rollers 24 on the selector levers in engagement with the corresponding control members |8,' a position will be reached very shortly in the cycle of operation wherein the selector levers are stopped against further pivotal move ment. .This situation is illustrated in Fig. 6 with reference to twoselector levers 23, one of the two levers being directly behind the other so that only a single lever is shown in the drawings. The

intermediate staggered selector levers 2 3' are eli-l minated from this drawing sovas not to confuse theillustration of the elements principally considered.` As can be seen, however, the control members i6 are at a position of 90 with respect to one another, and act in the same manner as a recess 26 Vto cause the stopping of the selector levers. Damage to the operating. mechanism is prevented, however, by virtue of the torsionvspring 36 which 'permits the driving arm 32 to' be pushed in a clockwise directionV to enable the commutator disc'29 to complete its rotation and open the motor energizing circuit through the contacts 6I. In the position of the kcontrol members in Fig. 6,

the stop 35 on the driving arm Ahas been pushed from a consideration 1 oi 1 a considerable distance beyond engagement with the edge ofthe latch member 33.

'I'he shaft I1, and consequently the tuning condenser I2, can be rotated manually to any angular position by means of control apparatus including the horizontally extending shaft 18 having a tuning knob 11 on the end thereof, and journalled in a pair of ears 18 stamped out of the ,end wall of the chassis I8 as shown in Figs. 7

and l2. The shaft 16 extends at right angles to the shaft I1 and mechanical connection between the two is accomplished by means of a belt or cord B extending around the pulley P on the shaft I1 and wound at its ends around the shaft 18. This same mechanism is used to vary the frictional pressure on the control members |8 to permit the angular adjustment of each of the control members with reference to the shaft I1 to set said control members at a predetermined angular position corresponding to the condenser setting for a desired broadcast or transmittingstation tuning setting. Shaft 18 is longitudinally movable as well as rotatable, and is provided with a pinion gear 18 iixedly secured to the shaft in a position such that upon pulling the shaft outwardly the gear is brought into mesh with teeth on a rack portion in a vertically slidable adjusting member 8|. Such rack portion on the member 8| is designated by the reference character 82 and stands at right angles to the body of such member. A second rack portion 83 lies in the plane of the body of the member 8| for engagement with the threaded friction gear 22 threadably secured on the shaft I1. The member 8| is `mounted upon guide pins 84 supported on the chassis I8 and positioned in vertical slots 82 and moves up and down freely upon rotation of the shaft I 1 and gear 22 thereon.

To reduce the frictional pressure exerted on the control members I8 by the washers I8, in order to adjust the angular position of such control members, the shaft 16 is pulled outwardly against the pressure of the spring 81 carried thereon to pulLthe gear 19 into engagement with the teeth on the rack portion 82 of the slidable member 8|. Assuming that a right-hand thread is provided in the gear 22 on the shaft I1, the knob 11 is rotated to rotate the gear 22 and shaft I1 in a counter-clockwise direction until the fixed arm 92 on the shaft |1 engages the rearward stop 9| stamped out of the end plate I4 of the tuner frame. This limits the rotation of the shaft I1 to this. position and upon further rotation of .the knob 11, the threaded gear 22 is threadably moved to the left as viewed in Fig. 1

to permit the washer and sleeve assembly on the shaft 11 to open up and reduce the friction intermedlate the washers I8 and control members I8. In this connection it is understood that the pulley P is axially slidable upon rthe shaft I1 in the same manner as the washer I9, and sleeve 2|, as well as the control members I 8, as is apparent from a consideration of Fig. 11. The pulley, however, is keyed against rotation on the shaft. Permitting the shaft 16 to be'retracted under the force of the spring 81, the driving connection with the gear 22 is eliminated, and the shaft I1 may be turned by the pulley P and the belt B thereon as for normal manual tuning. The condenser is then rotated to an angular position corresponding to a desired tuning setting by the knob 11 and associated mechanism, and then, holding the condenser in this position by holding the knob 11, a push-button 54 is pressed to close an electrical operating circuit therefor operating 'principally inexpensive stamped out parts.

through. VThe motor M rotates, and the latch member 88 is locked with a selector lever corresponding to the energized electromagnet l2 in the same manner as described above. With the shaft I1 'held against rotation, but the control member corresponding Ito the energized electromagnet free to rotate on the shaft I1 by virtue of the reduction of the frictional pressure thereon, the selected selector lever moves such control member I8 until the roller 24 is seated in the recess 28 for 'the control member. 'I'his same operation may be followed with respect to all six control members I8 to thereby provide settings for such control members corresponding to a like number of tuning positions for the condenser I2. y

The shaft 18 may again be pulled outwardly engagement with the member 8|, and rotating the shaft in the opposite direction in this instance, the arm 82 is rotated until it is stopped against a projection 8| spaced from the projection 9|' approximately 180, and then on continued rotation of the shaft 18 the threaded gear 22 is rotated and moved axially to the right to move the entire axially slidable assembly therewith. vA coupling member or stop as 88 flxedly secured on the shaft I1 at the right end of the assembly, as viewed in Fig. 1, acts to limit the axial movement of the assembly in that direction so that continued adjustment of the threaded gear 22 will increase rthe friotional pressure of the'washers I9 in the slidable assembly against the control members I8 therebetween.

Manual adjustment vof the tuning condenser for tuningover the entire broadcast range, and adjustment thereof for setting of the control members I8 may be followed by watching Vthe pointer 0 connected with the pulley P and moved over the dial D on the front of the receiver in the usual-manner.

A modification of our invention is illustrated in Figs. 13 and 14 of the drawings. The modifications from the preferred embodiment, however, pertain only to the apparatus itself and the circuit of Fig. 15 is used in the modification as well as in the preferred embodiment. The modification merely extends the control apparatus assembly axially, and provides identical selector levers |8I supported on a shaft 24 in the same manner as the preceding structure.. The latch member |82 is provided in a straight U-shaped bar pivotally supported on the shaft 24 as contrasted to the latch member 83 having a staggered leading edge thereon 'to correspond 'to the staggered positioning of the selector levers 23 and 23'. Similarly, the electromagnets |83 are all mounted in a straight line on a bracket |84 carried on the tuner frame to attract the plungers 41 carried on the selector levers |8I in the same manner as previously described. The entire operation of the commutator disc 29 and the associated driving elements including the driving arm 32 is identical with the structure of the preferred embodiment, and a further description thereof is believed not to be necessary.

In practicing our invention, therefore, we provide a simplified foolproof electrically operated control apparatus for a radio -receiver requiring control apparatus is actuated by a'unidirectional motor which is normally less expensive than a reversible motor and as a result of rotating a1- ways in a single direction, the adjustment of the tuning apparatus is effected in the most expeditious manner. f

The

angular /distance less operatively connecting said invention in its preferred embodiments,v it is understood that modifications therein maybe made all Within the spirit and scope of the invention, and the invention, therefore, is not limited by the above description and drawings', but is limited only by the scope of theappended claims.

We claim: Y

l. Control apparatus fora radioreceiver-including a movable control unit, rotary loperating means therefor rotating continuously while energized, through cycles ot 360 each, :means limiting the movement of said control unit to `an control unit and said rotary operating means including spring means within said coupling means transmitting the enthanV 360, coupling means` Y i ment of tire operating force from said operating #means l to said control unit, with said spring means being yieldable in aV rotary direction upon the stoppage ofthe control unit at one of its limiting positions to permit the continued rotationrof saidV rotary operating means through said cycles while the control unit remains stopped at said limiting position.

2. Electric control apparatus including control means rotatable through less than 360, axis means for said control means and driving means rotatable entirely through 360 operatively con-y nected with said control means,"with said operative connection including a pair of pivoted members pivoting through less than 360 connected togetherin a manner to normally move in unison and pivoting inl planes substantiallyat right angles to said axis means, but'with said connection yieldable to permit one of the two pivoted members to move while .the other member remains stationary in a completecycle of operation voi the control apparatus and for permitting continued rotation Vof the driving means through 360 without injury to the apparatus.

3. Control `apparatus for a radio receiver including a control unit and operating means therefor, with said control unit including a rotatable control member connected with tuning means for the radio receiver,'a pivoted selector lever for each control member, and means for driving said selector lever,v means including a movable armature and said lever and said driving means and spring means connected with said driving means and operatively connected with said operating means for connecting said control unit and said operating means to transmit an actuating force from the latter to the former. f'

4. Control apparatus for a radio receiver including in combination a control unit and operating means therefor, said operating means com-V prising a motor, a rotary driving member connectedtherewith rotating through 360 upon energigation of the motor to operate vthe apparatus,.a pivoted driving arrn'in continuous engagement with said .driving member pivoting always through less 'than 360, and springmeans intermediate said driving armA and said control unit and operatively connected to each for transmitting an operating driving force from said arm to said control unit.

5. Electrically operated control apparatus comprising control means including a plurality oi selector members, a pivoted driving member common to all of said selector members to selectively ymove said selector members through a restricted angular path', a rotary driving member rotatable entirelyv through 360 in mechanical a magnet for connecting Y l substantially identical .mined positions, said upon i energization fing said control members,l

connection with saidpivoted driving member, a motor actuating said rotarydriving member, an electric control circuit tor said apparatus including said motor therein, and a control switch in said circuit mechanically connected with said rotary driving member for operation upon movesaid rotary driving'member.

6. In controll apparatus for a radio receiver, control means for adjusting the angular position or a tuning unit for a radio receiver, means for driving said control means to selected Vpredeterdrivingmeans comprising a'pivoted latch member, a drivingarm independent of said control means operatively connected with said latch member, with said operative connection -including a spring member having one end connected with said-latch member and the other end connected withk said driving arm, Iwith said driving arm adapted for pivotal movement through less than 360, and means rotatable entirely through 360'in engagement 'with said driving arm for moving the same.

each cam for mechanical engagement with saidcam to move the same to a predetermined position, electro-magnetic means adjacent Y said selector levers, driving means common to all. oi said selector levers and means for connecting a preselected selector lever with said'driving means of said Y electro-magnetic means, and operating means for said driving means to move the latter to in turn'move the preselected lever and a corresponding cam therewith to adjust the tuning device for the radio receiver. y a

8. Electrically operated tuning apparatus for a radio receiver including a plurality of control members, a shaft in mechanical connection with a tuning device for said radio receiver for carrya movable selector member corresponding to each dividually connecting a preselected selector memmeans, said connecting ber with saidY driving means including said electro-magnetic means and a spring-pressed connecting member movable, on each selector memberadapted to be attracted to said electro-magnetic means upon energization ofthe sameto extend into the path of said driving means to be engaged thereby upon actuation of said driving means, means for actuating said driving means,l and 'an electric control circuit'for said apparatus includingsaid actuating means for said electro-magneticmeans therein. i' Y 9. An electric control unit for controllable apparatus including a plurality o! control members, a shaft for carrying said control members, a plurality of corresponding selector members for said control members pivotally supported ad- .'jacent thereto for engagement therewith, 'with said selector members provided in such a configuration that the portion of each selector member adjacent a corresponding control member is in conguration, and the 'remaining portion of each selector member is of such-` a` connguration that alternate selector control member )and adapted Yfor mechanical engagement theremembers are positioned to one side and then to the other side of a plane extending radially from the pivotal point for said selector members to provide a staggered positioning for said portions over the entire plurality of selector members,

electro-magnetic means supported adjacent one end of the selector members but spaced there;Tf

from having a portion for attracting a,y metallic element thereto, a piyoted connecting member intermediate the selector members and said electro-magnetic means having a staggered configuration corresponfiing to the staggered relationship of selectorg membersfmeans including said electro-magnetic means for selectively connecting a selector member with said connecting member, and means'y for driving said connecting member to drive said selector members and control members therewith.

10. An electrical control unitl for controllable apparatus including a plurality of control members, a shaft for carrying said-control members, a plurality of corresponding selector members for said control members pivotally' supported adjacent thereto for engagement therewith, with each of said selector members being substantially identical in configuration and supported in axial alignment, electro-magnetic means' supported adjacent one end of the selector members but spaced therefrom having a portion for attracting a metallic element thereto, a pivoted substantially U-shaped connecting member having 'a connecting portion extending in a straight line intermediate the selector members and said electro-magnetic means, means including said electro-magnetic means for selectively connecting a selector member with said connecting member, and means for driving said connecting member to drive said selector members and, control members therewith.

11. In an electric control system for controllable apparatus, an energizing source, an electric motor, a control switch for said system, a plurality of control uni-ts, and means includelectro-magnetic means for connecting said moving means with said control units, a plurality of control circuits including contact means and said electro-magnetic means in series therewith, with each of 'such control circuits in parallel connection lwith one another, but in series conneetion with the energizing source, the motor,

;.an d`,.-;Said operating switch, said system( also including resistance means in parallel connection vwith said cpntrol circuits and in series connection with said energizing source, said motor, and said operating switch, rotary means driven by said motor for operating said switch tov cut a selected control circuit vout of electrical connectionwith said motor and substantially Vsimultaneously therewith cut said resistance into series connection with said energizing source, said motor, and' said switch to continue the operation of said motor, with said rotary operating means operatively connected with said means for moving said control units to move a preselected control unit to a predetermined position, and contact means for selective closing'to originally energize said motor and electro-magnetic means.

1 12. Electrically operated tuning apparatus for a radio receiver including a plurality of control members, a shaft connected witha tuning device for said radio receiver for carrying said control member,l a"'pivoted selector member corresponding to each control member for moving the same to a predetermined control position, electro-magnetic means adjacent said selector cycle for said apparatus.

army and with said rotary shaft velectro-magnetic means,

members, driving means intermediate said electro-magnetic means and said selector members and means for connecting said selector members with said driving means upon energization of the an electric driving motor, av control switch, a circuit including said electro-magnetic means, said motor and said control switch, rotary means operatedby said motor tom'echanically actuate said switch, with said switch in a position initially in an operating cycle for said apparatus to connect said electromagnetic means into said circuit but movable by 'said rotary means to subsequently in the operating cycle cut outsthe electro-magnetic means from said circuit but maintain said circuit through said motor so as to energize said motor during the remainder of the complete operatingv 13. In radio control apparatus having a rotary shaft, frequency changing means operatively connected with said shaft, and power meansl for driving said shaft, the combination of a switch electrically connected to said power means, a driving member rotatable through 360 operatively connected with said power means and in physical engagement with said switch to operate the same, a pivoted -arm pivotable through less than 360 in physical engagement with said driving member and being driven thereby, and con'. necting means operatively connected with said to move the shaft in a control operation.

14. In. radio control apparatus having rotary Vcontrol means including a plurality of control units and a supporting shaft therefor with said units being adjustable relative to said shaft, the combination of a rotary driving motor for all ofv said control units, and coupling means for oper atively connecting said rotary driving motor and selected solenoid upon energization thereof, and

movable means within said coupling means operatively connected with said armature portion and operatively connected with said rotary Adriven means to transmit the driving power of the rotary motor to move the selected control unit to a predetermined position.

, 15. In radio control apparatushaving rotary i* control means including a plurality vof control units and a supporting shaft therefor with said units being adjustable relative to said shaft, the combination of a rotaryl driving motor for all of said control units, and coupling means for operatively connecting sald'rotary driving motor and a selected control unit including a rotary driven y all selector members releasably latched to the attracted armature, and means operatively connecting said gate and rotary drivenmeans to vtransmit the driving power of the rotary motor to move the selected control unit to a predetermined position.

ALEXANDER W. PLENSLER. RICHARD C. MARHOLZ. 

